1. Field of the Invention
The present invention relates to a rotary shearing machine which has upper and lower shearing disks or rotary tools for shearing sheet materials such as sheet metals therebetween, and more particularly to a so-called gang slitting machine which has a plurality of pairs of upper and lower rotary shearing tools so as to slit sheet materials such as sheet metals into narrower strips of desired width.
2. Description of the Prior Art
The so-called gang slitting machines are provided with a plurality of pairs of upper and lower disk-like shearing tools which are formed at their peripheries with cutting edges and are designed to be rotated like wheels. The upper shearing tools and the lower shearing tools are aligned to be rotated around horizontal upper and lower axes, respectively, in a manner such that each upper shearing tool and each lower shearing tool cooperate with each other. Thus, the upper and lower shearing tools are designed to cooperate with one another to slit a wide sheet material into narrower strips. Since the widths of the strips to be made depend upon the axial or horizontal lengths or distances between the pairs of the upper and lower shearing tools, all the shearing tools are so designed as to be axially or horizontally adjusted by placing, for example, spacers therebetween so as to slit the sheet material into strips of desired width.
In conventional gang slitting machines, the upper and the lower shearing tools are mounted on two parallel elongated shafts or arbors which are supported only at their ends by and between side frames of the machine.
Accordingly, one of fundamental disadvantages with the conventional gang slitting machines has been that it is very troublesome and time-consuming to set and reset the shearing tools onto and from the shafts or arbors holding them. When it is necessary to change or reset the shearing tools in the conventional gang slitting machines, it has been necessary to remove the long and heavy shafts from the machine and then detach many of the shearing tools axially from the ends of the shafts and finally re-position the shafts onto the machine. Also, even if only one of the shearing tools is damaged and is required to be replaced, for example, it has been necessary to remove the entire shaft supporting the damaged shearing tool from the machine and then detach many sound tools axially from the shaft to take out the damaged tool.
The greatest disadvantage of the conventional gang slitting machines, has been the troublesome and time-consuming effort required, each time it is necessary to adjust or change the axial lengths or distances between the pairs of the upper and lower shearing tools according to the widths of strips to be slit from sheet metals or worksheets. In order to adjust the axial lengths between the shearing tools for desired widths of strips to be slit, it has been necessary to remove and re-position both of the upper and lower shafts holding the tools from and onto the machine so as to place spacers of desired thickness between the shearing tools. Since it is very frequently needed to adjust or change the axial lengths between the shearing tools for various widths of strips to be slit, this troublesome and time-consuming effort has been very often required in the conventional gang slitting machines.
Another disadvantage with the conventional gang slitting machines has been the fact that the upper and lower shafts or arbors holding the shearing tools will be bent in opposite directions away from each other owing to the shearing reaction during shearing operations. Accordingly, the shearing tools could not be kept normal to the worksheet to be slit during shearing operations. As a result, accurate shearing could not be performed and also the shearing tools have been liable to earlier and more frequent damage in the conventional gang slitting machines.
In addition to the above, the conventional gang slitting machines have suffered from various shortcomings, and especially there has been no gang slitting machine that can be fully automatically operated.